Laser desorption/ionization method and mass spectrometry method

ABSTRACT

A laser desorption/ionization method includes a first process of preparing a sample support body. The sample support body includes a substrate, an ionization substrate, and a support that supports the ionization substrate with respect to the substrate such that a first surface of the ionization substrate is separated from the substrate. A plurality of through-holes are formed at least in measurement regions of the ionization substrate. A conductive layer is provided on peripheral edges of the through-holes at least on the second surface. Further, the laser desorption/ionization method includes a second process of dropping the sample on the measurement regions of the ionization substrate, and a third process of, after the sample has infiltrated into the ionization substrate, ionizing components of the sample by applying a laser beam to the second surface while applying a voltage to the conductive layer.

TECHNICAL FIELD

The present disclosure relates to a laser desorption/ionization methodand a mass spectrometry method.

BACKGROUND ART

Conventionally, a technique for performing mass spectrometry by applyinga laser beam to a sample, ionizing a compound in the sample, anddetecting the ionized sample is known. Patent Literature 1 discloses atechnique for performing ionization on a sample by disposing a fixingplate in which a plurality of through-holes (in units of mm) areprovided on a holding plate, dropping the sample on the holding platethrough the through-holes, and applying a laser beam to the sample.Patent Literature 2 discloses a technique for performing ionization on asample by dropping the sample to which a matrix is added on a substratein which a plurality of non-through-holes (in units of μm) are providedand applying a laser beam to the sample infiltrated into thenon-through-holes.

CITATION LIST Patent Literature

[Patent Literature 1] Japanese Unexamined Patent Publication No.2014-21048

[Patent Literature 2] U.S. Pat. No. 7,695,978

SUMMARY OF INVENTION Technical Problem

In the above techniques, in a case where an amount of the sample droppedin recesses is too much, there is a risk of the sample overflowing outof the recesses, a so-called unevenness effect (an effect of energy ofthe laser beam being easily transmitted to the sample by an unevenstructure) being lost, and ionization efficiency of the sample beingreduced. That is, there is a risk that components in the sample may beprevented from being properly ionized or that an amount of detected ionswill be reduced. As a result, there is a risk that sufficient signalintensity will not be obtained in the aforementioned mass spectrometryand the components in the sample will not be properly detected.

Therefore, the present disclosure is directed to providing a laserdesorption/ionization method and a mass spectrometry method capable ofinhibiting a reduction in ionization efficiency caused by a droppedamount of a sample.

Solution to Problem

A laser desorption/ionization method according to an aspect of thepresent disclosure includes a first process of preparing a samplesupport body. The sample support body includes a substrate; anionization substrate disposed on the substrate; and a support configuredto support the ionization substrate with respect to the substrate suchthat a first surface of the ionization substrate facing the substrateand the substrate are separated from each other. The ionizationsubstrate has measurement regions for dropping a sample on a secondsurface located on a side opposite to the first surface. A plurality ofthrough-holes that open in the first surface and the second surface areformed at least in the measurement regions of the ionization substrate.A conductive layer is provided on peripheral edges of the through-holesat least on the second surface. Further, the laser desorption/ionizationmethod includes a second process of dropping the sample on themeasurement regions of the ionization substrate; and a third process of,after the sample has infiltrated into the ionization substrate, ionizingcomponents of the sample by applying a laser beam to the second surfacewhile applying a voltage to the conductive layer.

In the sample support body prepared in the first process of the laserdesorption/ionization method, a gap is formed between the first surfaceof the ionization substrate and the substrate by the support. Thus, inthe second process, even if an amount of the sample dropped on thesecond surface of the ionization substrate is more than a proper amount,an excess of the sample can be released to the gap between the firstsurface of the ionization substrate and the substrate via thethrough-holes provided in the ionization substrate. For this reason, theexcess of the sample is inhibited from overflowing onto the secondsurface. As a result, in the third process, a reduction in ionizationefficiency when components of the sample are ionized by applying a laserbeam to the second surface is inhibited. As described above, accordingto the laser desorption/ionization method, a reduction in ionizationefficiency caused by the dropped amount of the sample can be inhibited.

A laser desorption/ionization method according to another aspect of thepresent disclosure includes a first process of preparing a samplesupport body. The sample support body includes a substrate; anionization substrate configured to have conductivity and disposed on thesubstrate; and a support configured to support the ionization substratewith respect to the substrate such that a first surface of theionization substrate facing the substrate and the substrate areseparated from each other. The ionization substrate has measurementregions for dropping a sample on a second surface located on a sideopposite to the first surface. A plurality of through-holes that open inthe first surface and the second surface are formed at least in themeasurement regions of the ionization substrate. Further, the laserdesorption/ionization method includes a second process of dropping thesample on the measurement regions of the ionization substrate; and athird process of, after the sample has infiltrated into the ionizationsubstrate, ionizing components of the sample by applying a laser beam tothe second surface while applying a voltage to the ionization substrate.

In the laser desorption/ionization method, the ionization substratehaving conductivity is prepared, and thus the sample support body inwhich the conductive layer is omitted can be used. Further, like thecase where the sample support body includes the conductive layer asdescribed above is used, a reduction in ionization efficiency caused bya dropped amount of the sample can be inhibited.

A laser desorption/ionization method according to yet another aspect ofthe present disclosure includes a first process of preparing a samplesupport body. The sample support body includes a substrate; and anionization substrate disposed on the substrate. The ionization substratehas measurement regions for dropping a sample on a second surfacelocated on a side opposite to a first surface facing the substrate. Aplurality of through-holes that open in the first surface and the secondsurface are formed at least in the measurement regions of the ionizationsubstrate. A conductive layer is provided on peripheral edges of thethrough-holes at least on the second surface. At least a part of thesubstrate located adjacent to the ionization substrate is formed toenable the sample to move inside the substrate. Further, the laserdesorption/ionization method includes a second process of dropping thesample on the measurement regions of the ionization substrate; and athird process of, after the sample has infiltrated into the ionizationsubstrate, ionizing components of the sample by applying a laser beam tothe second surface while applying a voltage to the conductive layer.

In the sample support body prepared in the first process of the laserdesorption/ionization method, at least a part of the substrate which islocated adjacent to the ionization substrate is formed to enable thesample to move inside the substrate. Thus, in the second process, evenif an amount of the sample dropped on the second surface of theionization substrate is more than a proper amount, an excess of thesample flowing into the substrate via the through-holes provided in theionization substrate can be released inside the substrate. For thisreason, the excess of the sample is inhibited from overflowing onto thesecond surface. As a result, in the third process, a reduction inionization efficiency when components of the sample are ionized byapplying a laser beam to the second surface is inhibited. As describedabove, according to the laser desorption/ionization method, a reductionin ionization efficiency caused by the dropped amount of the sample canbe inhibited.

A laser desorption/ionization method according to still yet anotheraspect of the present disclosure includes a first process of preparing asample support body. The sample support body includes a substrate; andan ionization substrate configured to have conductivity and disposed onthe substrate. The ionization substrate has measurement regions fordropping a sample on a second surface located on a side opposite to afirst surface facing the substrate. A plurality of through-holes thatopen in the first surface and the second surface are formed at least inthe measurement regions of the ionization substrate. At least a part ofthe substrate which is located adjacent to the ionization substrate isformed to enable the sample to move inside the substrate. Further, thelaser desorption/ionization method includes a second process of droppingthe sample on the measurement regions of the ionization substrate, and athird process of, after the sample has infiltrated into the ionizationsubstrate, ionizing components of the sample by applying a laser beam tothe second surface while applying a voltage to the ionization substrate.

In the laser desorption/ionization method, the ionization substratehaving conductivity is prepared, and thus the sample support body inwhich the conductive layer is omitted can be used. Further, like thecase where the sample support body including the conductive layer asdescribed above is used, a reduction in ionization efficiency caused bya dropped amount of the sample can be inhibited.

A mass spectrometry method according to an aspect of the presentdisclosure includes each process of the aforementioned laserdesorption/ionization method, and a fourth process of detecting thecomponents ionized in the third process.

Since the mass spectrometry method includes each process of theaforementioned laser desorption/ionization method, a reduction inionization efficiency caused by a dropped amount of the sample can beinhibited.

Advantageous Effects of Invention

According to the present disclosure, a laser desorption/ionizationmethod and a mass spectrometry method capable of inhibiting a reductionin ionization efficiency caused by a dropped amount of a sample can beprovided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a top view of a sample support body according to a firstembodiment.

FIG. 2 is a sectional view of the sample support body along line II-IIillustrated in FIG. 1.

FIG. 3 is an enlarged sectional view of major parts illustratingschematic configurations of an ionization substrate and a conductivelayer of the sample support body illustrated in FIG. 1.

FIG. 4 is a view illustrating an enlarged image of the ionizationsubstrate of the sample support body illustrated in FIG. 1.

FIG. 5 is a schematic view illustrating processes of a mass spectrometrymethod according to an embodiment.

FIG. 6 is a schematic view illustrating processes of a laserdesorption/ionization method according to a comparative example.

FIG. 7 is a view illustrating a sample support body according to asecond embodiment.

FIG. 8 is an enlarged sectional view of major parts illustrating aschematic configuration of a portion surrounded by a broken line Aillustrated in FIG. 7.

FIG. 9 is a view illustrating a sample support body according to a thirdembodiment.

FIG. 10 is a view illustrating sample support bodies according to fourthto sixth embodiments.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the drawings. Note that the sameor equivalent portions are denoted by the same reference signs in eachof the drawings, and duplicate descriptions thereof will be omitted.Dimensions of each member (or each region) illustrated in the drawingsor ratios of the dimensions may be different from actual dimensions orratios of the actual dimensions in order to facilitate understanding ofthe description.

First Embodiment

A sample support body 1 according to a first embodiment will bedescribed with reference to FIGS. 1 to 3. FIG. 1 is a top view of thesample support body 1. FIG. 2 is a sectional view of the sample supportbody 1 along line II-II illustrated in FIG. 1. FIG. 3 is an enlargedsectional view of major parts illustrating schematic configurations ofan ionization substrate 3 and a conductive layer 4 of the sample supportbody 1. As illustrated in FIGS. 1 to 3, the sample support body 1includes a substrate 2, an ionization substrate 3, a conductive layer 4,a support 5, and tapes (fixing members) 6. The substrate 2 is formed,for instance, in a rectangular plate shape. Hereinafter, forconvenience, a direction parallel to long sides of the substrate 2 maybe referred to as an X direction, a direction parallel to short sides ofthe substrate 2 may be referred to as a Y direction, and a thicknessdirection of the substrate 2 may be referred to as a Z direction. The Zdirection is also a direction in which the substrate 2 and theionization substrate 3 face each other.

The substrate 2 is formed of, for instance, a conductive material. Forexample, the substrate 2 is formed of a slide glass, a metal, etc.having conductivity. The slide glass having conductivity is, forinstance, a glass substrate on which a transparent conductive film suchas an ITO film is formed (an indium tin oxide (ITO) slide glass).Lengths of the short and long sides of the substrate 2 are, forinstance, around a few centimeters. A thickness of the substrate 2 is,for instance, about 1 mm. When the sample support body 1 is placed on asample stage (a stage) of a mass spectrometry device (not illustrated),the substrate 2 is a portion that comes into contact with the samplestage.

The ionization substrate 3 is formed of, for instance, an insulatingmaterial in a rectangular plate shape. The ionization substrate 3 can beformed, for instance, by anodizing a valve metal or silicon. In thepresent embodiment, lengths of short sides (sides parallel to the Ydirection) of the ionization substrate 3 are the same as those of theshort sides of the substrate 2, and lengths of long sides (sidesparallel to the X direction) of the ionization substrate 3 are set to beshorter than those of the long sides of the substrate 2. A thickness ofthe ionization substrate 3 is, for instance, about 1 μm to 50 μm. Theionization substrate 3 is disposed above the substrate 2, and has afirst surface 3 a that faces the substrate 2 and a second surface 3 bthat is located on a side opposite to the first surface 3 a. When viewedin the Z direction, the ionization substrate 3 is disposed above thesubstrate 2 such that the long sides of the ionization substrate 3overlap those of the substrate 2, and the center of the ionizationsubstrate 3 overlaps that of the substrate 2.

As illustrated in FIG. 1, the ionization substrate 3 has a plurality ofmeasurement regions R for dropping a sample on the second surface 3 b. Ashape of each of the measurement regions R is, for instance, a circularshape whose diameter is around a few millimeters (e.g., 3 mm). In thepresent embodiment, the ionization substrate 3 has seven measurementregions R disposed at regular intervals in the X direction, and fourmeasurement regions R disposed at regular intervals in the Y direction.A mark or the like for an operator to identify each of the measurementregions R may be added to the ionization substrate 3, but these marks orthe like may not be added. That is, the second surface 3 b of theionization substrate 3 may have regions that can be large enough to setthe plurality of measurement regions R. In this case, the measurementregions R are set off by members other than the ionization substrate 3such as, for instance, first support 5 b to be described below, and thusthe measurement regions R can be identified by an operator who performsmeasurement using the sample support body 1.

As illustrated in FIG. 3, a plurality of through-holes 3 c are formeduniformly (with a uniform distribution) at least in the measurementregions R of the ionization substrate 3. In the present embodiment, theplurality of through-holes 3 c are uniformly formed in the entire secondsurface 3 b of the ionization substrate 3. Each of the through-holes 3 cextends in the Z direction (the direction perpendicular to the first andsecond surfaces 3 a and 3 b), and opens in the first and second surfaces3 a and 3 b. Shapes of the through-holes 3 c when viewed in the Zdirection are, for instance, approximately circular shapes. Widths ofthe through-holes 3 c are, for instance, about 1 nm to 700 nm. Thewidths of the through-holes 3 c are diameters of the through-holes 3 cin the case where the shapes of the through-holes 3 c when viewed in theZ direction are, for instance, approximately circular shapes, and arediameters (effective diameters) of imaginary maximum columns fitted intothe through-holes 3 c in the case where the shapes of the through-holes3 c are shapes other than the approximately circular shapes.

FIG. 4 is a view illustrating an enlarged image of the ionizationsubstrate 3 when viewed in the thickness direction of the ionizationsubstrate 3. In FIG. 4, black portions are equivalent to thethrough-holes 3 c, and white portions are equivalent to partitionsbetween the through-holes 3 c. As illustrated in FIG. 4, the pluralityof through-holes 3 c having approximately a constant width are uniformlyformed in the ionization substrate 3. An opening ratio of thethrough-holes 3 c in the measurement regions R (a ratio of the wholethrough-holes 3 c to the measurement regions R when viewed in thethickness direction of the ionization substrate 3) is practically 10 to80%, and particularly preferably 60 to 80%. Sizes of the plurality ofthrough-holes 3 c may be irregular, and the plurality of through-holes 3c may be partly coupled to one another.

The ionization substrate 3 illustrated in FIG. 4 is an alumina porousfilm formed by anodizing aluminum (Al). To be specific, the ionizationsubstrate 3 can be obtained by performing anodization treatment on an Alsubstrate and peeling an oxidized surface portion from the Al substrate.The ionization substrate 3 may be formed by anodizing a valve metalother than Al such as tantalum (Ta), niobium (Nb), titanium (Ti),hafnium (Hf), zirconium (Zr), zinc (Zn), tungsten (W), bismuth (Bi),antimony (Sb), or the like, or by anodizing silicon (Si).

The conductive layer 4 is a layer formed of a conductive materialprovided to impart conductivity to the insulating ionization substrate3. However, even in the case where the ionization substrate 3 is formedof a conductive material, providing the conductive layer 4 is notobstructed. The conductive layer 4 is at least provided at peripheraledges of the through-holes 3 c on the second surface 3 b. As illustratedin FIG. 3, the conductive layer 4 covers a portion of the second surface3 b at which the through-holes 3 c are not formed. That is, openings ofthe through-holes 3 c which are adjacent to the second surface 3 b arenot blocked by the conductive layer 4.

A metal having a low affinity (reactivity) with a sample and highconductivity is preferably used as the material of the conductive layer4 due to reasons that will be mentioned below. For example, when theconductive layer 4 is formed of a metal such as copper (Cu) having ahigh affinity with a sample such as a protein, there is a risk of thesample being ionized with Cu atoms attached to sample molecules in aprocess of ionizing the sample to be described below, and of a detectedresult in a mass spectrometry method to be described below deviating inproportion as the Cu atoms are attached. Therefore, a metal having a lowaffinity with a sample is preferably used as the material of theconductive layer 4.

Meanwhile, as the conductivity of a metal becomes higher, a constantvoltage is easily applied in an easier and more stable way. For thisreason, when the conductive layer 4 is formed of a metal having highconductivity, a voltage can be uniformly applied to the second surface 3b of the ionization substrate 3 in the measurement regions R. Further, ametal having higher conductivity also shows a tendency to have higherthermal conductivity. For this reason, when the conductive layer 4 isformed of a metal having high conductivity, energy of a laser beamapplied to the ionization substrate 3 can be efficiently transmitted toa sample via the conductive layer 4. Therefore, a metal having highconductivity is preferably used as the material of the conductive layer4.

In view of this, for example, gold (Au), platinum (Pt), or the like ispreferably used as the material of the conductive layer 4. For example,the conductive layer 4 is formed at a thickness of about 1 nm to 350 nmby a plating method, an atomic layer deposition (ALD) method, a vapordeposition method, a sputtering method, or the like. For example,chromium (Cr), nickel (Ni), titanium (Ti), or the like may be used asthe material of the conductive layer 4.

The support 5 is a member that supports the ionization substrate 3 withrespect to the substrate 2 such that the first surface 3 a of theionization substrate 3 and the substrate 2 are separated from eachother. The support 5 functions as a gap forming member for forming a gapbetween the first surface 3 a of the ionization substrate 3 and asurface 2 a of the substrate 2 which faces the ionization substrate 3.In the present embodiment, when viewed in the Z direction, a contour ofthe support 5 has a rectangular plate shape having nearly the same sizeas the ionization substrate 3. Further, a thickness of the support 5 is,for instance, about 40 μm.

When viewed in the Z direction, through-holes 5 a having shapescorresponding to the measurement regions R (here, circular shapes havinga diameter of 3 mm) are formed in portions of the support 5 whichoverlap the plurality of measurement regions R. That is, when viewed inthe Z direction, the support 5 has a first support 5 b (peripheral edgeportions of the through-holes 5 a) provided between peripheral edges ofthe measurement regions R on the first surface 3 a and the substrate 2to separate the plurality of measurement regions R. Further, the support5 also has a second support 5 c (a portion that overlaps a peripheraledge of the ionization substrate 3) provided between the peripheral edgeof the ionization substrate 3 (when viewed in the Z direction, a portionlocated outside regions in which the plurality of measurement regions Rare provided) and the substrate 2.

The first support 5 b is a portion that is equivalent to partitionsbetween the plurality of through-holes 5 a, and is formed to regulatethe plurality of measurement regions R. The first support 5 b is formedof, for instance, a bonding member that bonds the first surface 3 a ofthe ionization substrate 3 and the surface 2 a of the substrate 2. To bespecific, the first support 5 b is, for instance, a conductivedouble-sided tape, a conductive vacuum adhesive, or the like. Accordingto the first support 5 b, the ionization substrate 3 can be fixed to thesurface 2 a of the substrate 2 while a gap between the first surface 3 aof the ionization substrate 3 and the surface 2 a of the substrate 2 issecured. Here, the plurality of through-holes 3 c are provided in theionization substrate 3, and the ionization substrate 3 and theconductive layer 4 are very thin. For this reason, when the samplesupport body 1 is seen from the vicinity of the second surface 3 b ofthe ionization substrate 3, boundaries of the through-holes 5 a and thefirst support 5 b are seen. Thus, an operator who performs measurementusing the sample support body 1 can visually recognize each of themeasurement regions R. In addition, according to the first support 5 b,an excess of the sample dropped on one of the measurement regions R canbe prevented from moving to other measurement regions R via the gapbetween the first surface 3 a of the ionization substrate 3 and thesurface 2 a of the substrate 2 (i.e., the samples dropped on thedifferent measurement regions can be prevented from mixing with eachother).

The second support 5 c is a portion that is equivalent to an outercircumferential frame of the support 5, and is formed to surround theplurality of measurement regions R. According to the second support 5 c,the ionization substrate 3 can be stably supported with respect to thesubstrate 2 while the gap between the first surface 3 a of theionization substrate 3 and the surface 2 a of the substrate 2 issecured. The second support 5 c is formed of, for instance, a bondingmember that bonds the first surface 3 a of the ionization substrate 3and the surface 2 a of the substrate 2. To be specific, the secondsupport 5 c is, for instance, a conductive double-sided tape, aconductive vacuum adhesive, or the like. In this case, the ionizationsubstrate 3 can be fixed to the surface 2 a of the substrate 2 by thesecond support 5 c.

The tapes 6 are members that have conductivity and fix edges along theshort sides of the ionization substrate 3 to the substrate 2. The tapes6 function as fixing members that fix the ionization substrate 3 and thesubstrate 2 to each other in contact with the conductive layer 4. Asillustrated in FIG. 2, in the present embodiment, the tapes 6 are bondedto the conductive layer 4 (here, the portion that covers an uppersurface of the edges along the short sides of the second surface 3 b ofthe ionization substrate 3) and the surface 2 a of the substrate 2 topress the ionization substrate 3 against the substrate 2. The ionizationsubstrate 3 can be reliably fixed to the substrate 2 by the tapes 6.Further, in a case where the substrate 2 has conductivity, electricalconnection between the substrate 2 and the conductive layer 4(electrical connection for applying a voltage to the conductive layer 4)can be performed via the tapes 6. Thus, a configuration for the aboveelectrical connection can be simplified.

Next, a mass spectrometry method (including a laserdesorption/ionization method) using the sample support body 1 will bedescribed. FIG. 5 is a schematic view illustrating processes of a massspectrometry method according to the present embodiment. In FIG. 5, theconductive layer 4 is not illustrated.

First, the aforementioned sample support body 1 is prepared (a firstprocess). The sample support body 1 is manufactured by a person whoperforms the mass spectrometry method or is obtained from a manufactureror a seller thereof, and thereby the sample support body 1 may beprepared.

Next, as illustrated in FIG. 5(A), a sample S is dropped on one of themeasurement regions R in the ionization substrate 3 (a second process).Here, a gap is formed between the first surface 3 a of the ionizationsubstrate 3 and the surface 2 a of the substrate 2 by the aforementionedsupport 5. For this reason, in a case where an amount of the sample Sdropped on the second surface 3 b of the ionization substrate 3 is morethan a proper amount, an excess of the sample S is made to flow into thegap between the first surface 3 a of the ionization substrate 3 and thesurface 2 a of the substrate 2 via the through-holes 3 c provided in theionization substrate 3 due to gravity. On the other hand, because widthsof the through-holes 3 c are extremely small, ranging from 1 nm to 700nm, the sample S ionized by applying a laser beam to the second surface3 b can be suitably maintained in the through-holes 3 c. Thus, asillustrated in FIG. 5(B), after the sample S has infiltrated into theionization substrate 3 (after the sample S is dried), the excess of thesample S is released into the gap between the first surface 3 a of theionization substrate 3 and the surface 2 a of the substrate 2, whereas aproper amount of the sample S required for ionization remains in thethrough-holes 3 c.

Next, the sample support body 1 and the sample S are placed, forinstance, on a stage of a mass spectrometry device (not illustrated).Then, as illustrated in FIG. 5(C), a voltage is applied to theconductive layer 4 (see FIG. 2) of the sample support body 1 via thesurface 2 a of the substrate 2 and the tapes 6 (see FIG. 2) by a voltageapplication unit 101 of the mass spectrometry device (a third process).Then, a laser beam L is applied to the second surface 3 b of theionization substrate 3 by a laser beam emission unit 102 of the massspectrometry device (the third process). That is, the laser beam L isapplied to the measurement region R on which the sample S is dropped.

In this way, the laser beam L is applied to the second surface 3 b ofthe ionization substrate 3 while the voltage is applied to theconductive layer 4. Thus, components of the sample S (especially, thesample S around the opening of the through-hole 3 c which is locatedadjacent to the second surface 3 b) that remains in the through-hole 3 cformed in the ionization substrate 3 are ionized, and sample ions SI(the ionized components) are discharged (a fourth process). To bespecific, energy is transmitted to the components of the sample S thatremains in the through-hole 3 c formed in the ionization substrate 3from the conductive layer 4 (see FIG. 3) that absorbs energy of thelaser beam L, the components obtaining the energy evaporate, and chargesare obtained to become the sample ions SI. The above first to fourthprocesses correspond to the laser desorption/ionization method using thesample support body 1.

The discharged sample ions SI move toward a ground electrode (notillustrated) provided between the sample support body 1 and a detector103 of the mass spectrometry device while accelerating. That is, thesample ions SI move toward the ground electrode due to a potentialdifference generated between the conductive layer 4 to which the voltageis applied and the ground electrode while accelerating. Then, the sampleions SI are detected by the detector 103 (a fifth process). Here, themass spectrometry device uses a time-of-flight mass spectrometry(TOF-MS) method. The above first to fifth processes correspond to themass spectrometry method using the sample support body 1.

FIG. 6 is a schematic view illustrating processes of a laserdesorption/ionization method according to a comparative example. To bespecific, FIG. 6 illustrates an outline of a conventionalsurface-assisted laser desorption/ionization (SALDI) method. In thelaser desorption/ionization method according to the comparative example,a substrate 300 having a fine uneven structure on a surface thereof isused. To be specific, first, a sample S is dropped on one measurementspot of the substrate 300 (a surface on which the uneven structure ofthe substrate 300 is provided) (FIG. 6(A)). Here, a space for releasingan excess of the sample S is not provided in the substrate 300, like thesample support body 1. For this reason, in a case where a dropped amountof the sample S is more than a proper amount, after the sample Sinfiltrates into the surface of the substrate 300 (after the sample S isdried), the excess of the sample S overflows out of the uneven structureof the substrate 300 (i.e., the uneven structure is buried in the sampleS) (FIG. 6(B)). For this reason, a so-called unevenness effect (aneffect of energy of the laser beam being easily transmitted to thesample by the uneven structure) is not produced, and ionizationefficiency of the sample S when a laser beam is applied to the surfaceof the substrate 300 is reduced (FIG. 6(C)). On the other hand, asdescribed above, according to the laser desorption/ionization methodusing the sample support body 1, since the excess of the sample S isprevented from overflowing onto the second surface 3 b of the ionizationsubstrate 3, a reduction in the ionization efficiency of the sample Scan be inhibited.

As described above, in the sample support body 1, the gap is formedbetween the first surface 3 a of the ionization substrate 3 and thesubstrate 2 by the support 5. Thus, even if the amount of the sample Sdropped on the second surface 3 b of the ionization substrate 3 is morethan a proper amount, the excess of the sample S can be released intothe gap between the first surface 3 a of the ionization substrate 3 andthe substrate 2 via the through-holes 3 c provided in the ionizationsubstrate 3. For this reason, the excess of the sample S is inhibitedfrom overflowing onto the second surface 3 b, and the reduction inionization efficiency when the components of the sample S are ionized byapplying the laser beam L to the second surface 3 b is inhibited.Further, in the sample support body 1, the plurality of measurementregions R set off by the first support Sb are used, and thus thecontinuous measurement of the sample S can be performed. As describedabove, according to the sample support body 1, the continuousmeasurement of the sample S can be performed while inhibiting thereduction in ionization efficiency caused by the dropped amount of thesample S.

Further, since the substrate 2 is formed of a conductive slide glass ora conductive metal, the electrical connection for applying a voltage tothe conductive layer 4 can be performed via the substrate 2. As aresult, the configuration for the electrical connection can besimplified.

Further, the ionization substrate 3 is formed by anodizing a valve metalor silicon. In this case, due to the anodization of the valve metal orthe silicon, the ionization substrate 3 in which the plurality of finethrough-holes 3 c are provided can be realized in a proper and easy way.

Further, the widths of the through-holes 3 c range from 1 nm to 700 nm.Thus, the sample S for ionization through application of the laser beamL to the second surface 3 b can suitably remain in the through-hole 3 cwhile the excess of the sample S dropped on the second surface 3 b ofthe ionization substrate 3 is caused to move to the gap between thefirst surface 3 a of the ionization substrate 3 and the substrate 2 viathe through-hole 3 c.

Further, the sample support body 1 includes the tapes 6 that haveconductivity and fix the ionization substrate 3 and the substrate 2 incontact with the conductive layer 4. For this reason, the ionizationsubstrate 3 can be reliably fixed to the substrate 2 by the tapes 6.Further, in the case where the substrate 2 has conductivity, theelectrical connection between the substrate 2 and the conductive layer 4(the electrical connection for applying a voltage to the conductivelayer 4) can be performed via the tapes 6. Thus, the configuration forthe electrical connection can be simplified.

Further, in the sample support body 1 prepared in the first process ofthe aforementioned laser desorption/ionization method, the gap is formedbetween the first surface 3 a of the ionization substrate 3 and thesubstrate 2 by the support 5. Thus, even if the amount of the sample Sdropped on the second surface 3 b of the ionization substrate 3 is morethan a proper amount in the second process, the excess of the sample Scan be released to the gap between the first surface 3 a of theionization substrate 3 and the substrate 2 via the through-hole 3 cprovided in the ionization substrate 3. For this reason, the excess ofthe sample S is inhibited from overflowing onto the second surface 3 b.As a result, the reduction in ionization efficiency when the componentsof the sample S are ionized by applying the laser beam L to the secondsurface 3 b is inhibited in the third process. As described above,according to the laser desorption/ionization method, the reduction inionization efficiency caused by the dropped amount of the sample can beinhibited.

Second Embodiment

A sample support body 1A according to a second embodiment will bedescribed with reference to FIGS. 7 and 8. FIG. 7A is a top view of thesample support body 1A. FIG. 7B is a sectional view of the samplesupport body 1A along line B-B of FIG. 7A. FIG. 8 is an enlargedsectional view of major parts illustrating a schematic configuration ofa portion surrounded by a broken line A illustrated in FIG. 7. Asillustrated in FIGS. 7 and 8, the sample support body 1A is differentfrom the sample support body 1 in that the sample support body 1Aincludes a frame 7 and disposition of a conductive layer 4 and tapes 6is partly changed, and the other configurations are the same as in thesample support body 1.

When viewed in a direction in which a substrate 2 and an ionizationsubstrate 3 face each other (a Z direction), the frame 7 is at leastformed on a peripheral edge of a second surface 3 b in the ionizationsubstrate 3. In the present embodiment, when viewed in the Z direction,a contour of the frame 7 has a rectangular plate shape having nearly thesame size as the ionization substrate 3. Further, a thickness of theframe 7 is, for instance, 1 mm or less. The frame 7 is formed of, forinstance, a metal.

When viewed in the Z direction, through-holes 7 a having shapescorresponding to a plurality of measurement regions R (here, circularshapes having a diameter of 3 mm) are formed in portions of the frame 7which overlap the plurality of measurement regions R. That is, whenviewed in the Z direction, the frame 7 has a wall 7 b (peripheral edgeportions of the through-holes 7 a) provided on peripheral edges of themeasurement regions R on the second surface 3 b to separate theplurality of measurement regions R. Further, the frame 7 also has anouter edge 7 c (a portion that overlaps a peripheral edge of theionization substrate 3) provided on the peripheral edge of the secondsurface 3 b of the ionization substrate 3 (when viewed in the Zdirection, a portion located outside regions in which the plurality ofmeasurement regions R are provided).

The wall 7 b is a portion that corresponds to partitions between theplurality of through-holes 7 a, and is formed to regulate the pluralityof measurement regions R. Thus, an operator who performs measurementusing the sample support body 1 can visually recognize each of themeasurement regions R. Further, according to the wall 7 b, for example,when a sample is dropped on one of the measurement regions R, a part ofthe sample can be prevented from being scattered to other measurementregions R adjacent to one of the measurement regions R. The outer edge 7c is a portion that correspond to an outer circumferential frame of theframe 7 having a rectangular plate shape, and is formed to surround theplurality of measurement regions R.

As illustrated in FIG. 8, the frame 7 (the wall 7 b and the outer edge 7c) is fixed to the second surface 3 b of the ionization substrate 3 byan adhesive layer 8. An adhesive material that emits little gas (e.g.,low melting point glass, an adhesive for vacuum, or the like) ispreferably used as a material of the adhesive layer 8. Further, in thesample support body 1A, the conductive layer 4 is continuously(integrally) formed on regions of the second surface 3 b of theionization substrate 3 (i.e., the measurement regions R) whichcorrespond to the openings (the through-holes 7 a) of the frame 7, innersurfaces of the through-holes 7 a, and a surface 7 d of the frame 7which is located on a side opposite to the ionization substrate 3. Thatis, the conductive layer 4 is formed to further cover the surface 7 d ofthe frame 7. Thus, as will be described below, electrical connection forapplying a voltage to the conductive layer 4 can be performed on theframe 7. In the measurement regions R, like the sample support body 1,the conductive layer 4 covers a portion of the second surface 3 b atwhich the through-holes 3 c are not formed. That is, openings of thethrough-holes 3 c which are adjacent to the second surface 3 b are notblocked by the conductive layer 4.

Further, in the sample support body 1A, the tapes 6 function as fixingmembers that fix the ionization substrate 3 and the substrate 2 to eachother in contact with a portion of the conductive layer 4 which coversthe surface 7 d of the frame 7. To be specific, the tapes 6 are bondedto the conductive layer 4 (here, the portion that covers the surface 7d) and a surface 2 a of the substrate 2 to press the ionizationsubstrate 3 against the substrate 2 from the top of the outer edge 7 cof the frame 7. The substrate 2, the ionization substrate 3, and theframe 7 can be reliably fixed to one another by the tapes 6. Further, ina case where the substrate 2 has conductivity, the electrical connectionbetween the substrate 2 and the conductive layer 4 (the electricalconnection for applying a voltage to the conductive layer 4) can beperformed via the tapes 6. Thus, a configuration for the aboveelectrical connection can be simplified. Especially, since theelectrical connection can be performed on the surface 7 d of the frame7, the electrical connection can be realized without corroding theeffective regions (i.e., the measurement regions R) on the ionizationsubstrate 3.

In the sample support body 1A, like the sample support body 1, a gap isformed between the first surface 3 a of the ionization substrate 3 andthe substrate 2 by a support 5. Thus, even if an amount of the sample Sdropped on the second surface 3 b of the ionization substrate 3 is morethan a proper amount, an excess of the sample S can be released to thegap between the first surface 3 a of the ionization substrate 3 and thesubstrate 2 via the through-holes 3 c provided in the ionizationsubstrate 3. For this reason, the excess of the sample S is inhibitedfrom overflowing out on the second surface 3 b, and a reduction inionization efficiency when components of the sample S are ionized byapplying a laser beam L to the second surface 3 b is inhibited. Further,in the sample support body 1A, the plurality of measurement regions Rset off by the wall 7 b of the frame 7 are used, and thus continuousmeasurement of the sample S can be performed. As described above,according to the sample support body 1A, the continuous measurement ofthe sample S can be performed while inhibiting the reduction inionization efficiency caused by the dropped amount of the sample S.

Third Embodiment

A sample support body 1B according to a third embodiment will bedescribed with reference to FIG. 9. FIG. 9(A) is a top view of thesample support body 1B. FIG. 9(B) is a sectional view of the samplesupport body 1B (a top view of a substrate 12) along line B-B of FIG.9(A). As illustrated in FIG. 9, the sample support body 1B is differentfrom the sample support body 1 in that the sample support body 1Bincludes the substrate 12 instead of the substrate 2, and the otherconfigurations are the same as in the sample support body 1.

A plurality of through-holes 12 a extending in a direction (a Zdirection) in which the substrate 12 and an ionization substrate 3 faceeach other are provided in the substrate 12 to correspond to a pluralityof measurement regions R. In the present embodiment, when viewed in theZ direction, each of the through-holes 12 a has a circular shape havingthe same size as each of the corresponding measurement regions R. Thatis, when viewed in the Z direction, the through-holes 12 a overlapcorresponding through-holes 5 a of a support 5. However, when viewed inthe Z direction, the through-holes 12 a may not necessarily completelyoverlap the corresponding measurement regions R and through-holes 5 a.Further, contours of the through-holes 12 a viewed in the Z directionmay not necessarily be identical to those (here, circular shapes havinga diameter of 3 mm) of the corresponding measurement regions R andthrough-holes 5 a. That is, the contours of the through-holes 12 aviewed in the Z direction may be smaller or larger than those of thecorresponding measurement regions R and through-holes 5 a.

In the sample support body 1B, at least a part of the substrate 12 whichis adjacent to the ionization substrate 3 is formed to enable a sample Sto be moved inside the substrate 12. To be specific, the plurality ofthrough-holes 12 a are formed in the substrate 12. For this reason, thesample S overflowing out of openings of through-holes 3 e which areadjacent to a first surface 3 a of the ionization substrate 3 toward thesubstrate 12 can be moved into the through-holes 12 a of the substrate12. That is, an excess of the sample S can be released to thethrough-holes 12 a provided in the substrate 12 to correspond to themeasurement regions R. Thus, even if an amount of the sample S droppedon a second surface 3 b of the ionization substrate 3 is more than aproper amount, the excess of the sample S flowing into the substrate 12via the through-holes 3 c provided in the ionization substrate 3 can bereleased inside the substrate 12 (here, inner portions of thethrough-holes 12 a). For this reason, the excess of the sample S isinhibited from overflowing out on the second surface 3 b, and areduction in ionization efficiency when components of the sample S areionized by applying a laser beam L to the second surface 3 b isinhibited. As described above, according to the sample support body 1B,the reduction in ionization efficiency caused by the dropped amount ofthe sample S can be inhibited. Further, in the sample support body 1B,the plurality of measurement regions R prepared on the second surface 3b of the ionization substrate 3 are used, and thus continuousmeasurement of the sample S can be performed.

Further, in the sample support body 1B, since the excess of the sample Scan be released outside the substrate 12 (a side opposite to thevicinity of the ionization substrate 3) via the through-holes 12 aformed in the substrate 12, the excess of the sample S can be moreeffectively discharged.

Further, in a case where the sample support body 1B is used instead ofthe sample support body 1 in the aforementioned laserdesorption/ionization method, even if the amount of the sample S droppedon the second surface 3 b of the ionization substrate 3 is more than aproper amount in the second process, the excess of the sample S flowinginto the substrate 12 via the through-holes 3 c provided in theionization substrate 3 can be released inside the substrate 12 (here,the inner portions of the through-holes 12 a). For this reason, theexcess of the sample S is inhibited from overflowing out on the secondsurface 3 b. As a result, the reduction in ionization efficiency whenthe components of the sample S are ionized by applying the laser beam Lto the second surface 3 b is inhibited in the third process. Asdescribed above, according to the laser desorption/ionization methodusing the sample support body 1B, the reduction in ionization efficiencycaused by the dropped amount of the sample S can be inhibited.

Fourth Embodiment

FIG. 10(A) is a view illustrating a sample support body 1C according toa fourth embodiment. The sample support body 1C is different from thesample support body 1B in that the sample support body 1C includes asubstrate 22 instead of the substrate 12, and the other configurationsare the same as in the sample support body 1B.

A plurality of recesses 22 b are provided in a surface 22 a of thesubstrate 22 which is adjacent to an ionization substrate 3 tocorrespond to a plurality of measurement regions R. In the presentembodiment, when viewed in a Z direction, openings of the recesses 22 bhave circular shapes having the same size as the correspondingmeasurement regions R. That is, when viewed in the Z direction, therecesses 22 b overlap corresponding through-holes 5 a of a support 5.However, when viewed in the Z direction, the recesses 22 b may notnecessarily completely overlap the corresponding measurement regions Rand through-holes 5 a. Further, contours of the recesses 22 b viewed inthe Z direction may not necessarily be identical to those (here,circular shapes having a diameter of 3 mm) of the correspondingmeasurement regions R and through-holes 5 a. That is, the contours ofthe recesses 22 b viewed in the Z direction may be smaller or largerthan those of the corresponding measurement regions R and through-holes5 a.

Like the sample support body 1B, in the sample support body 1C, at leasta part of the substrate 22 which is adjacent to the ionization substrate3 is also formed to enable a sample S to be moved inside the substrate22. To be specific, the plurality of recesses 22 b are formed in thesurface 22 a of the substrate 22 which faces the ionization substrate 3.For this reason, the sample S overflowing out of openings ofthrough-holes 3 c which are adjacent to a first surface 3 a of theionization substrate 3 toward the substrate 22 can be moved into therecesses 22 b of the substrate 22. That is, an excess of the sample Scan be released to the recesses 22 b provided in the substrate 22 tocorrespond to the measurement regions R. Thus, the same effects as theaforementioned sample support body 1B are obtained.

Fifth Embodiment

FIG. 10(B) is a view illustrating a sample support body 1D according toa fifth embodiment. The sample support body 1D is different from thesample support body 1B in that the sample support body 1D includes asubstrate 32 instead of the substrate 12, and the other configurationsare the same as in the sample support body 1B.

Like the sample support body 1B, in the sample support body 1D, at leasta part of the substrate 32 which is adjacent to an ionization substrate3 is formed to enable a sample S to be moved inside the substrate 32. Tobe specific, the substrate 32 is formed of a material having absorbency.The substrate 32 is formed of, for instance, a resin such as urethane, aporous metal, a ceramic, or the like. For this reason, the sample Sreaching the substrate 32 via through-holes 3 c of the ionizationsubstrate 3 is absorbed into the substrate 32, and thereby the excess ofthe sample S can be released inside the substrate 32. Thus, the sameeffects as the aforementioned sample support bodies 1B and 1C areobtained.

Sixth Embodiment

FIG. 10(C) is a view illustrating a sample support body 1E according toa sixth embodiment. The sample support body 1E is different from thesample support body 1B in that the sample support body 1E does notinclude a support 5 and a first surface 3 a of an ionization substrate 3is in contact with a surface of a substrate 12, and the otherconfigurations are the same as in the sample support body 1B. Thesupport 5 is omitted in the sample support body 1E, and thus a gap isnot formed between the first surface 3 a of the ionization substrate 3and the substrate 12. Like the sample support body 1B, in this samplesupport body 1E, a sample S overflowing out of openings of through-holes3 c which are adjacent to the first surface 3 a of the ionizationsubstrate 3 toward the substrate 12 can be moved into through-holes 12 aof the substrate 12, by the through-holes 12 a formed in the substrate12. That is, like the aforementioned sample support bodies 1B to 1D, anexcess of the sample S can also be inhibited from overflowing out on asecond surface 3 b by the sample support body 1E, and a reduction inionization efficiency caused by a dropped amount of the sample S can beinhibited.

In the sample support body 1C or 1D, the support 5 may also be omitted.Even in this case, since the sample support body 1C or 1D includes theaforementioned substrate 22 or substrate 32, the excess of the sample Scan be inhibited from overflowing out on the second surface 3 b, and thereduction in ionization efficiency caused by the dropped amount of thesample S can be inhibited. However, like the sample support body 1B to1D, even in the case where the aforementioned substrates 12, 22 and 32are used, the gap may be formed between the first surface 3 a of theionization substrate 3 and the substrate 12, 22 or 32 by the support 5.In this case, since the excess of the sample S can be further releasedto the gap between the first surface 3 a of the ionization substrate 3and the substrate 12, 22 or 32, the excess of the sample S can be moreeffectively inhibited from overflowing out on the first surface 3 a.

Modifications

While embodiments of the present disclosure have been described, thepresent disclosure is not limited to the above embodiments, and can bevariously modified without departing the subject matter thereof. Forexample, the configurations of the aforementioned sample support bodies1, and 1A to 1E may be appropriately combined. For example, the frame 7of the sample support body 1A may also be provided on the sample supportbodies 1B to 1E whose substrates are processed.

Further, the configurations of some of the sample support bodies 1, and1A to 1E may be appropriately omitted. For example, in the samplesupport body 1, in a case where the support 5 is the bonding member andthe ionization substrate 3 and the substrate 2 are sufficiently fixed bythe support 5, the tapes 6 may be omitted. Further, in the third processof the laser desorption/ionization method, a voltage may be applied tothe conductive layer 4 without using the substrate 2, 12, 22 or 32 andthe tapes 6. In this case, the substrate 2, 12, 22 or 32 and the tapes 6may not have conductivity.

Further, the ionization substrate 3 may have conductivity. To bespecific, the ionization substrate 3 may be formed of, for instance, aconductive material such as a semiconductor. In this case, a voltage maybe applied to the ionization substrate 3 in the third process. In thiscase, in the sample support bodies 1 and 1A to 1E, the conductive layer4 can be omitted, and the reduction in ionization efficiency caused bythe dropped amount of the sample can be inhibited like the case wherethe sample support bodies 1 and 1A to 1E including the conductive layer4 are used as described above.

For example, in a case where marking indicating boundaries of themeasurement regions R are provided on the second surface 3 b of theionization substrate 3, the configuration for setting of the pluralityof measurement regions R (in the above embodiments, the first support Sbor the wall 7 b of the frame 7) may be omitted. Further, in the casewhere both the support 5 and the frame 7 are provided like the samplesupport body 1A, the plurality of measurement regions R may be set offby at least one of the first support 5 b and the wall 7 b. Further, theionization substrate 3 may not necessarily have the plurality ofmeasurement regions R, and the number of measurement regions R may beone.

Further, the first support 5 b and the second support 5 c may not beintegrally formed. For example, the first support corresponding to oneof the measurement regions R may be a member that is providedindependently of the first support corresponding to the othermeasurement regions R. To be specific, when viewed in the Z direction,the first support corresponding to one of the measurement regions R maybe, for instance, a cylindrical member that is formed to overlap theperipheral edge of the measurement region R. Further, the second supportmay be a member that is provided independently of the first support. Tobe specific, when viewed in the Z direction, the second support may be,for instance, a member that has a rectangular frame shape and is formedto overlap the peripheral edge of the ionization substrate 3.

Further, the wall 7 b and the outer edge 7 c may not be integrallyformed. For example, the wall corresponding to one of the measurementregions R may be a member that is provided independently of the wallcorresponding to the other measurement regions R. To be specific, whenviewed in the Z direction, the wall corresponding to one of themeasurement regions R may be, for instance, a cylindrical member that isformed to overlap the peripheral edge of the measurement region R.Further, the outer edge may be a member that is provided independentlyof the wall. To be specific, when viewed in the Z direction, the outeredge may be, for instance, a member that has a rectangular frame shapeand is formed to overlap the peripheral edge of the ionization substrate3.

Further, at least one of the plurality of measurement regions R may beused as a region for mass calibration. Before measurement of the sampleto be measured (the aforementioned mass spectrometry method) isinitiated, the measurement is performed by dropping a sample for masscalibration (e.g., peptide or the like) to the measurement region R thatis set as the region for mass calibration, and thus a mass spectrum canbe corrected. The correction of this mass spectrum is performed beforethe measurement of the sample to be measured, and thus an accurate massspectrum of the sample to be measured when the sample to be measured ismeasured can be obtained.

Further, the laser desorption/ionization method (the first to thirdprocesses) can be also used in the mass spectrometry of the sample Sdescribed in the present embodiment as well as other measurements andexperiments such as ion mobility measurement.

Further, use of the sample support bodies 1 and 1A to 1E is not limitedto the ionization of the sample S caused by the application of the laserbeam L. The sample support bodies 1 and 1A to 1E may be used in theionization of the sample S caused by application of an energy beam(e.g., an ion beam, an electron beam, etc.) other than the laser beam L.That is, in the laser desorption/ionization method, in place of thelaser beam L, the energy beam other than the laser beam L may beapplied.

REFERENCE SIGNS LIST

-   -   1, 1A, 1B, 1C, 1D, 1E Sample support    -   2, 12, 22, 32 Substrate    -   3 Ionization substrate    -   3 a First surface    -   3 b Second surface    -   3 c Through-hole    -   4 Conductive layer    -   5 Support    -   5 a Through-hole    -   5 b First support    -   5 c Second support    -   6 Tape (fixing member)    -   7 Frame    -   7 a Through-hole    -   7 b Wall    -   7 c Outer edge    -   L Laser beam    -   R Measurement region    -   S Sample

1: A laser desorption/ionization method comprising: a first process ofpreparing a sample support body including: a substrate; an ionizationsubstrate disposed on the substrate; and a support configured to supportthe ionization substrate with respect to the substrate such that a firstsurface of the ionization substrate facing the substrate and thesubstrate are separated from each other, the ionization substrate havingmeasurement regions for dropping a sample on a second surface located ona side opposite to the first surface, a plurality of through-holes thatopen in the first surface and the second surface being formed at leastin the measurement regions of the ionization substrate, and a conductivelayer being provided on peripheral edges of the through-holes at leaston the second surface; a second process of dropping the sample on themeasurement regions of the ionization substrate; and a third process of,after the sample has infiltrated into the ionization substrate, ionizingcomponents of the sample by applying a laser beam to the second surfacewhile applying a voltage to the conductive layer. 2: A laserdesorption/ionization method comprising: a first process of preparing asample support body including: a substrate; an ionization substrateconfigured to have conductivity and disposed on the substrate; and asupport configured to support the ionization substrate with respect tothe substrate such that a first surface of the ionization substratefacing the substrate and the substrate are separated from each other,the ionization substrate having measurement regions for dropping asample on a second surface located on a side opposite to the firstsurface, and a plurality of through-holes that open in the first surfaceand the second surface being formed at least in the measurement regionsof the ionization substrate; a second process of dropping the sample onthe measurement regions of the ionization substrate; and a third processof, after the sample has infiltrated into the ionization substrate,ionizing components of the sample by applying a laser beam to the secondsurface while applying a voltage to the ionization substrate. 3: A laserdesorption ionization method comprising: a first process of preparing asample support body including: a substrate; and an ionization substratedisposed on the substrate, the ionization substrate having measurementregions for dropping a sample on a second surface located on a sideopposite to a first surface facing the substrate, a plurality ofthrough-holes that open in the first surface and the second surfacebeing formed at least in the measurement regions of the ionizationsubstrate, a conductive layer being provided on peripheral edges of thethrough-holes at least on the second surface, and at least a part of thesubstrate located adjacent to the ionization substrate is formed toenable the sample to move inside the substrate; a second process ofdropping the sample on the measurement regions of the ionizationsubstrate; and a third process of, after the sample has infiltrated intothe ionization substrate, ionizing components of the sample by applyinga laser beam to the second surface while applying a voltage to theconductive layer. 4: A laser desorption/ionization method comprising: afirst process of preparing a sample support body including: a substrate;and an ionization substrate configured to have conductivity and disposedon the substrate, the ionization substrate having measurement regionsfor dropping a sample on a second surface located on a side opposite toa first surface facing the substrate, a plurality of through-holes thatopen in the first surface and the second surface being formed at leastin the measurement regions of the ionization substrate, and at least apart of the substrate located adjacent to the ionization substrate beingformed to enable the sample to move inside the substrate; a secondprocess of dropping the sample on the measurement regions of theionization substrate; and a third process of, after the sample hasinfiltrated into the ionization substrate, ionizing components of thesample by applying a laser beam to the second surface while applying avoltage to the ionization substrate. 5: A mass spectrometry methodcomprising: each process of the laser desorption/ionization methoddefined in claim 1; and a fourth process of detecting the componentsionized in the third process. 6: A mass spectrometry method comprising:each process of the laser desorption/ionization method defined in claim2; and a fourth process of detecting the components ionized in the thirdprocess. 7: A mass spectrometry method comprising: each process of thelaser desorption/ionization method defined in claim 3; and a fourthprocess of detecting the components ionized in the third process. 8: Amass spectrometry method comprising: each process of the laserdesorption/ionization method defined in claim 4; and a fourth process ofdetecting the components ionized in the third process.